There have been provided in the past many different types of incinerators for burning waste materials resulting from municipal trash collections, business or industrial plant operations, sewage systems, and the like. The materials to be consumed are necessarily varied not only in shape and composition but also in moisture content. As a result such materials are not always completely consumed in existing incinerators causing smoke and generation of clinkers or unburnt cakes of waste material which are impossible to reburn and must be otherwise gotten rid of.
An example of a prior art incinerator is shown in U.S. Pat. No. 3,605,656 to J. B. Stribling in which waste materials are fed by a conveyor onto a rotatable hearth in a combustion chamber and burnt during displacement from a peripheral portion of the hearth toward the center, the burnt material passing out through an ash outlet in the center of the hearth. During the displacement of the waste materials on the hearth, deflectors are provided for agitating the waste materials in an effort to increase the drying of the material, maximize combustion and reduce the formation of clinkers. Nevertheless, it has been found that the burning operation is not always complete in such a incinerator due to the wide variation in the nature and character of the waste materials supplied to the furnace.
Examplary of another type of furnace is shown in U.S. Pat. No. 3,772,998 having a multi-stage dryer for first drying waste material and a fluidized bed furnace for receiving the materials from the dryer and burning it under forced air and at high temperatures. The use of the dryer more satisfactorily drys the waste material permitting more complete combustion in the fluidized bed furnace, but the equipment is expensive to manufacture, is complicated in construction and costly to operate.